ATTENTION
Risque de décharge électrique
Débrancher l'alimentation avant de réaliser tout rac-
cordement électrique afin d'éviter tout risque de
décharge électrique.
Important:
Do not connect supply power
to the controller before finishing wiring and
checking all wiring connections. Short circuits
or improperly connected wires can result
in damage to the controller and void any
warranty.
Important:
Do not exceed the controller
electrical ratings. Exceeding controller electrical
ratings can result in permanent damage to the
controller and void any warranty.
Important:
Use copper conductors only. Make
all wiring in accordance with local, national, and
regional regulations.
Important:
Electrostatic discharge can
damage controller components. Use proper
electrostatic discharge precautions during
installation, setup, and servicing to avoid
damaging the controller.
For information on configuring and wiring
a BACnet/IP network, refer to the
Metasys IP
Networks for BACnet/IP Controllers Configuration
Guide (LIT-12012458).
For detailed information on
configuring and wiring a SA Bus, refer to the
MS/TP
Communications Bus Technical Bulletin (LIT-12011034).
Network topology
VMA1930 controllers may be connected to a building
automation network in multiple ways: as daisy-
chained devices, as part of a star (also called home
run) type network, or as part of a ring network.
To daisy-chain VMA1930 controllers, connect the
controllers to the bus supervisor in a chain with
the Ethernet cable connecting to the VMA1930
at the ETH1 or ETH2 port, and connecting to the
next device from the other port. Benefits of daisy-
chained networks are that they require less physical
wiring and new devices can be added easily to the
network.
In a star network, each VMA1930 controller is
connected by Ethernet cable directly back to a main
switch. This configuration reduces the possibility of
network failure but requires more wiring to install.
A ring network is a chain of controllers virtually
closed by a software component in an Ethernet
switch. Not all switches support the ring topology.
The dual-port controller from Johnson Controls
supports Media Redundancy Protocol (MRP). With
MRP, a chain of Ethernet devices can overcome any
single communication failure, with a recovery time
faster than in a BACnet system.
For more information about network topologies for
Metasys
BACnet/IP Controllers, refer to the
Metasys
IP Networks for BACnet/IP Controllers Configuration
Technical Bulletin (LIT-12012458)
.
VMA terminals and bus ports
for input and output
terminal and bus port locations on the controllers.
Observe the following guidelines when wiring a
VMA controller.
Input and Output terminals
The input spade terminals are located on the
bottom of the VMA near the FC Bus terminal block.
The output spade terminals are located on the top
of the controller near the power supply terminal
block. For more information, see Table 3.
SA Bus terminal block
The SA Bus terminal block is a brown, removable,
4-terminal plug with +15 VDC that fits into a board-
mounted jack. Wire the removable SA Bus terminal
block plugs on the VMA and other SA Bus devices
in a daisy-chain configuration using 4-wire twisted,
shielded cable as shown in Figure 3. See Table 5 for
more information.
Figure 3: SA bus terminal block wiring
VMA1930 VAV Controller Installation Guide
6